“True Adolescents” bears the dubious distinction of combining mumblecore’s penchant for artistic slackers with Hollywood’s celebration of immature slobs. The result is Sam (Mark Duplass, “The Puffy Chair” and “Humpday”), a 34-year-old unemployed rocker whose mediocre musicianship is matched only by his abysmal people skills; he’s like Jack Black without any energy or confidence. Saddled with a couple of adolescents on a camping trip gone wrong in the Pacific Northwest, Sam necessarily drops his callow, macho defensiveness in favor of a tentative maturity. Bowing July 29 in Gotham, helmer-scripter Craig Johnson’s indulgent freshman outing may prove an acquired taste.

Helmer Johnson handles his hero’s quasi-transformation with subtlety. But the endless round-robins of juvenile idiocy that precede it, underscored with requisite touches of angst, pall very quickly. Conversely, the pic’s overly tasteful nod toward adolescent sexual confusion makes one yearn for the confrontational rawness of Lynn Shelton’s “Humpday.” Thesping is fine throughout, Bret Loehr and Carr Thompson providing excellent teenage foils to Duplass’ puerile protag. And the all-too-brief presence of a radiantly down-to-earth Melissa Leo as Sam’s aunt evokes the existence of an entire world of grown-ups out there somewhere.

True Adolescents

Production

A Flatiron Film release of a Group Entertainment, Unison Films presentation in association with Lunacy Unlimited of a Furnace Film production. Produced by Thomas Woodrow. Executive producers, Gill Holland, Emanuel Michael. Co-producers, Stu Pollard, Jennifer Lee, Laurie Hicks. Directed, written by Craig Johnson.